Interlocking means for a pair of overlapping panels



Nov. 7, 1967 P. J. WOOD 3,351,263

INTERLOCKING MEANS FOR A PAIR OF OVERLAPPING PANELS Filed April 21, 1965 2 Sheets-Sheet 1 FIGI '1 \H/ 32 m' 1/ i \i fl Wig-:2

2% Wk WA R Wfiiji INVENTOR. PR' ENTICE J WOOD ATTORNEY Nov. 7, 1967 P. J. WOOD 3,351,263

INTERLOCKING MEANS FOR A PAIR OF OVERLAPPING PANELS Filed April 21, 1966 2 Sheets-Sheet 2 INVENTOR. PRENTICE J. WOOD ATTORNEY United States Patent 3,351,263 INTERLOCKING MEANS FOR A PAIR OF OVERLAPPING PANELS Prentice J. Wood, Jonesboro, Ga., assignor to The Mead Corporation, a corporation of Ohio Filed Apr. 21, 1966, Ser. No. 544,206 9 Claims. (Cl. 229-40) This invention relates to interlocking means for a pair of overlapping panels and more particularly to an improved locking mechanism for securing together a pair of overlapping panels in an open ended package wrapper.

In one known locking arrangement for securing together the overlapping panels of a tubular type package wrapper, a locking tab is driven through an opening defined by a retaining tab. While this type of lock constitutes an efiicient locking means and results in a secure package, it is necessary to use it in conjunction with primary packages the shape of which is such that open space is provided within the package.

In another known locking arrangement hook-like L- shaped locking tabs are arranged to move relative to their cooperating apertures in a direction transverse to the wrapper after the tightening operation is complete. This type of lock may be used in conjunction with square primary packages or packages of some other shape which do not provide space inside the wrapper. The transverse relative motion between the panels however poses a measure of complication which is inherent in providing a machine for interlocking this type of lock.

A principal object of this invention is to provide an improved interlocking arrangement which is adaptable for use in packages wherein vacant space is not provided inside the package and wherein the tension of the wrapper may be maintained without any relaxation during or after the formation of the lock and thereby to provide a wrapper which securely retains the articles therein against dislodgement through the open ends of the wrapper.

Another object of this invention is the provision of an improved locking arrangement which automatically serves to align the wrapper with the primary packages to be wrapped therein due to the particular cooperation between the elements to be interlocked.

Still another object of the invention is to provide an improved locking arrangement for a wrapper type carton which may be located medially of the carton or to either side of the medial center line of the carton.

The invention in one form as applied to a pair of overlapping panels comprises a locking strap struck out of one of said panels and foldably joined thereto along a hinge line, a pair of locking apertures formed in the other said panels and arranged so that said locking strap may be inserted through one of said locking apertures in one direction and through the other locking aperture in the other direction so as to form a buckled relation, and a positioning tab forming a part of the other panel and arranged for insertion into the opening defined in said one panel due to the formation of the locking strap, said panel, strap and tab being disposed in generally flat face contacting relation when in interlocked condition. According to a feature of the invention, the positioning tab is of tapered configuration and the cooperating aperture defined by the locking strap is similarly tapered so as to effect automatic alignment of the lock and panels. According to another feature of the invention a pair of locking shoulders may be formed on opposite sides of the locking strap and arranged to cooperate with corresponding locking slits formed along opposite edges of one of the locking apertures. According to still another facet of the invention, a separator panel is foldably joined to an edge of the one panel and foldably joined 3,351,263 Patented Nov. 7, 1967 thereto along a fold line which may be aligned with the hinge line of the locking strap and, if desired, one or more base tabs may be struck out of the separator panel and disposed in the plane of the one panel so as to improve the stability and the overall sturdiness of the lock. In order to facilitate the formation of the lock, a transverse weakened line may be formed in the locking strap if desired.

For a better understanding of the invention, reference may be had to the following detailed description taken in conjunction with the accompanying drawings in which FIG. 1 is a perspective view of a wrapper type package in which the overlapping ends of the wrapper are secured together by interlocking means according to this invention; FIG. 2 is a plan view from which the wrapper depicted in FIG. 1 is formed; FIG. 3 is a perspective view similar to a part of FIG. 1 but with the primary packages removed and showing the interlocking elements prior to engagement; FIG. 4 is a view similar to FIG. 3 and showing the locking strap and the positioning tab in the positions which they occupy initially and just as they enter their cooperating apertures and openings formed by the locking strap; FIGS. 5 and 6 show progressive stages during the formation of the lock and FIG. 7 shows the lock in complete locked condition.

With reference to the drawings, the numeral 1 denotes a main panel which ordinarily would be the top panel of the blank. In FIG. 1 the panel 1 is shown as the bottom panel for the sake of clarity and so as to expose the interlocking means of this invention. Formed in main panel 1 is a pair of finger gripping apertures 2 and 3 as well as a plurality of articles separating tabs 4, 5, and 6 which are struck out of the main panel 1 and foldably joined thereto along their respective hinge lines 7, 8 and 9. Side wall 10 is foldably joined to main panel 1 along a discontinuous fold line 11 in which a plurality of corner slits 12, 13, and 14 are formed in known manner. Similarly, side wall 15 is foldably joined to the opposite edge of main panel 1 along fold line 16 and a plurality of corner slits 17, 18 and 19 are formed in known manner along the fold line 16.

The panel opposite to main panel 1 is a composite panel made up of lap panels generally designated by the numerals 20 and 21. Lap panel 20 is foldably joined to side wall 10 along a discontinuous fold line 22 and a plurality of corner slits 23, 24 and 25 are formed in known manner along the fold line 22. Similarly, lap panel 21 is foldably joined to side Wall 15 along a discontinuous fold line 26 and a plurality of corner slits 27, 28 and 29 are formed along the fold line 26.

In order to tighten the wrapper about the primary packages C a pair of tightening apertures 30 and 31 are formed in lap panel 20 and a similar pair of tightening apertures 32 and 33 are formed in lap panel 21. Thus, as is well known in the art, machine elements enter the tightening apertures 30 and 31 and draw lap panel 20 toward lap panel 21 while corresponding machine elements enter tightening apertures 32 and 33 and move in the opposite direction so as to secure the wrapper tightly about the primary packages C.

For the purpose of separating one row of primary packages C from the other row of primary packages, a medial separator panel 34 is foldably joined to lap panel 21 along a discontinuous fold line 35.

In accordance with this invention, one or more locking straps 36, 37 and 38 are struck from lap panel 21 and are individually arranged to cooperate with a pair of locking apertures 39, 40, 41, 42, 43, 44. In addition, a plurality of positioning tabs are provided for each locking strap and its associated pair of locking apertures and in the drawings such positioning tabs are designated by the numerals 45, 46 and 47. Since all the locking straps, locking apertures and positioning tabs are identical in construction a detailed explanation of only locking strap 38 and its associated positioning tab 47 and locking apertures 43 and 44 will be included.

The locking strap 38 as best shown in FIG. 2 preferably is provided with a pair of oppositely disposed locking shoulders 48 and 49 which cooperate as will be explained in detail with the locking slits 50 and 51 formed in opposite sides of locking apertures 44. The corresponding parts of lap panel 21 are designated at 48A and 49A. In addition, locking strap 38 is provided with a weakened fold line 52 so as to facilitate the manipulation of the strap during the formation of an interlocking relationship.

For the purpose of improving stability of the wrapper and in order to guard against inadvertent tearing of the locking straps 36, 37 and 38, a plurality of base tabs are struck from the medial separator panel 34 and are arranged to remain in the plan of lap panel 21. Such base tabs are best shown in FIG. 2 and are designed by the numerals 53-58.

In order to facilitate the formation of the lock, a fold line 59 is formed in lap panel 20 and generally coincides with one edge of the locking apertures 39, 41 and 43 as shown in FIG. 2. Thus, the lap panel 20 is divided by fold line 59 into two portions one of which is called the tightening portion and incorporates the tightening apertures 30 and 31 and the other of which includes the locking apertures 39-44 as well as the positioning tabs 46-47 and may be referred to as the interlocking portion of the lap panel 20. The opening formed in lay panel 21 when locking strap 38 is struck out and swung out of the plane thereof is designated by the numeral 60. The tapered sides of positioning tab 47 are designated at 61 and 62.

With the parts disposed as depicted in FIG. 3, the locking strap 38 has been swung out of the plane of the lap panel 21 in a counter clockwise direction about the hinge line 35 and the interlocking portion of lap panel 20 has been rotated in a generally clockwise direction along the fold line 59. The tightening portion of lap panel 20 has been rotated in a generally clockwise direction along the fold line 22 and the locking aperture 43 is positioned to receive the locking strap 38 when moved in one general direction and generally toward the lap panel 20. Furthermore, the positioning tab 47 is positioned for entry within the tapered shoulder parts of the opening 60 formed in lap panel 21 due to the formation of locking strap 38. Thus the tapered shoulder portions 48A and 49A of the opening 60 cooperate with the tapered sides 61 and 62 of the positioning tap 47 so as to guide the interlocking portion of lap panel 20 into correct alignment with the lap panel 21 and with the primary packages which are not shown in FIG. 3. In addition to its guiding function, the positioning tab 47 also provides a holding function whereby the adjacent part of the interlocking portion of lap panel 20 is held in position to cover or close opening 60 partially and thereby engage and hold the locking strap 38 thereunder.

FIG. 4 shows the locking strap 38 after it is partially inserted into the locking aperture 43. FIG. 4 also shows the positioning tab 47 as it is about to enter the opening 60.

FIGS. 5 and 6 show progressive stages of the locking operation. In FIG. 5 the lap panels and 21 approach a position of parallelism and the positioning tab 47 almost fully occupies a position approaching the fully locked position. In FIG. 6 the positioning tab is shown in its fully locked position and the lap panels 20 and 21 are parallel, the locking strap 38 having been swung in a clockwise direction so that its hinge line 35 engages the locking and tightening edge 62 of locking aperture 43. Thus as the locking tab 38 is swung completely toward the right to occupy a position of flat parallel relationship to the lap panels 20 and 21, these two panels are securely held together. In FIG. 6 the end and shoulder portions 48 and 49 of the locking strap 38 are shown as inclined downwardly due to folding along the weakened fold line 52. After the lock is completed as shown in FIG. 7, the shoulder portions 48 and 49 occupy positions immediately beyond the locking slits 50 and 51.

In order to stabilize the carton and to prevent tearing or peeling of the inner surface of locking strap 38, the base tabs 57 and 58 are provided. As is shown in the drawings, these base tabs in effect are struck out of the medial separator panel 34 and form continuations of the lap panel 21 and occupy the same plane as that panel. Thus the elfect of the base panels 57 and 58 is to proxide a part of a hinge line 35 for locking strap 38 and also to prevent peeling off of a layer of material comprising a surface of the locking strap 38.

From the foregoing description, it is apparent that the interlocking means according to this invention is adapt able for use in wrapper type packages wherein the primary packages are of such shape as not to provide vacant space within the package and that relative transverse movement of the lap panels such as 20 and 21 is not necessary in order to complete the lock. Furthermore, it is apparent that the lock remains in tension as the lock is completed. Stated otherwise, it is not necessary to relax the tension of the package in order to finalize the locking poration due to the cooperation between the hinge line 35 of the locking straps such as 38 and the locking edge 62 of the locking aperture 43 and the corresponding edge of the remaining locking apertures 41 and 39. Furthermore, it is apparent that the lock of this invention may be located at the medial portion of the package as shown in the drawings but that the locking mechanism can be shifted to either side of the medial center line of the package. In this event the separator panel 34 is arranged differently as are the base tabs 53-58. Of course for some applications of the invention, the separator panel 34 may be omitted entirely.

While a particular embodiment of the invention has been shown and described, it will be understood that the invention is not limited thereto and it is intended in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of the invention.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. Interlocking means for a pair of overlapping panels comprising a locking strap struck out of one of said panels and foldably joined thereto along a hinge line, a pair of locking apertures formed in the other of said panels, said locking strap being arranged for insertion through one of said apertures in one direction and through the other of said apertures in the opposite direction to form therewith a buckled relation, and a positioning tab forming a part of said other panel and arranged for insertion into the opening defined in said one panel due to the formation of said locking strap, said panels, strap, and tab being disposed in generally flat face contacting relation when in locked condition.

2. Interlocking means according to claim 1 wherein said positioning tab is of tapered configuration and wherein the edge portion of the opening formed in said one panel due to the formation of said locking strap is similarly tapered so as to effect automatic alignment of said panels.

3. Interlocking means according to claim 1 wherein an edge portion of said one of said locking apertures is adjacent the hinge line of said locking strap when said panels are interlocked and wherein the distance between said edge portion and the outer extremity of said positioning tab is greater than the overall length of said locking strap.

4. Interlocking means according to claim 1 wherein a pair of locking shoulders are formed on opposite sides of said locking strap.

5. Interlocking means according to claim 4 wherein a pair of locking slits are formed at opposite parts of said other locking aperture for facilitating the formation and maintenance of a locking relation between said look ing strap and said other locking aperture.

6. Interlocking means according to claim 4 wherein a weakened bend line is formed transversely in said locking strap and between said locking shoulders and said hinge line to facilitate insertion of the end of said locking strap through said other locking aperture.

7. Interlocking means according to claim 1 wherein a separator panel is foldably joined to an edge of said one panel along a fold line which is aligned with the hinge line of said locking strap.

8. Interlocking means according to claim 7 wherein at least one base tab is struck out of said separator panel and disposed in the plane of said one panel and wherein at least a part of said hinge line for said locking strap constitutes a fold line between said base tab and said locking strap.

9. Interlocking means for a pair of overlapping panels comprising a locking strap forming a part of one of said panels and foldably joined thereto along a hinge line, an opening formed in said one panel adjacent said hinge line, a pair of locking apertures formed in the other of said panels, said locking strap being arranged for insertion through one of said apertures in one direction and through the other of said apertures in the opposite direction to form therewith a buckled relation, and a positioning tab forming a part of said other panel and arranged for insertion into said opening, said panels, strap, and tab being disposed in generally flat face contacting relation when in locked condition.

References Cited UNITED STATES PATENTS 1/1928 Galbraith et al 229- X; 2/1928 Galbraith et al 229-40 X 

1. INTERLOCKING MEANS FOR A PAIR OF OVERLAPPING PANELS COMPRISING A LOCKING STRAP STRUCK OUT OF ONE OF SAID PANELS AND FOLDABLY JOINED THERETO ALONG A HINGE LINE, A PAIR OF LOCKING APERTURES FORMED IN THE OTHER OF SAID PANELS, SAID LOCKING STRAP BEING ARRANGED FOR INSERTION THROUGH ONE OF SAID APERTURES IN ONE DIRECTION AND THROUGH THE OTHER OF SAID APERTURES IN THE OPPOSITE DIRECTION TO FORM THEREWITH A BUCKLED RELATION, AND A POSITIONING TAB FORMING A PART OF SAID OTHER PANEL AND ARRANGED FOR INSERTION INTO THE OPENING DEFINED IN SAID ONE PANEL DUE TO THE FORMATION OF SAID LOCKING STRAP, SAID PANELS, STRAP, AND TAB BEING DISPOSED IN GENERALLY FLAT FACE CONTACTING RELATION WHEN IN LOCKED CONDITION. 